Refrigeration apparatus



May15,v1945. `.3, R MAR@ f 2,375,859

REFRIGERA'IIONA APPARATUS Filed Dec. 6, 1940 ATTORN FIG- Y BY v Patented May 15, 1945 2,375,859 nEFmoEaAnoN APPARATUS Gerald P., Marcy, Longmeadow, Mass., assigner to Westinghouse Electric & Manufacturing Company, East Pittsburgh, Pa., a. corporation of Pennsylvania Application December 6, 1940, Serial No. 368,769

6 Claims.

This invention relates tol bimetallic thermostats and more especially to bimetallic thermostats adapted for installation in moist locations In temperature-controlling devices actuated by a bimetallic element it is necessary to have the bimetallic element at the 'location where the temperature is to be controlled. In refrigeratlng' apparatus this requires that the bimetallic element be placed adjacent the moist or irostf covered evaporator, The controlling devices usually comprise moving parts such as electric contacts and temperature-adjusting devices located adjacent'to -the bimetallic element and, tlfierefore, in the region of the moisture or frost on the evaporator and the usual expedient heretoi'ore has been to enclose the entire device in a sealed casing to protect the moving parts from moisture and frost. Where the devices were adinstable, the adjusting means usually comprised the use of flexible. bellows or the like to transmit the adjusting motion to the mechanism in the interior of the bellows.

@ne object of the invention is to provide a bimetallic control in which the electrical contacts the temperature-adjusting devices are remote from the bimetallic element.

Another object of the invention is to provide controlling devices adapted for controlling moist or frozen zones in which devices the currentconducting contacts do not require enclosures in a sealed casing.

Another object of the invention is to provide adjustable Ioiinetallic temperature-controlling devices adapted for controlling moist or frozen aones in which devices flexible seals or the like are eliminated.

These and other objects are effected by the invention as will be apparent from the following description and claims taken in connection with the accompanying drawing, forming a part of this application, in which:

Fig. 1 is a view of the thermostatic control of this invention partly in section and partly schematic showing its application for controlling a motor;

Fig. 2 is a sectionn view on the line n n of Fig. 1; and, Fig. 3 is an kelevation of a domestic refrigeratorwith the front wall of the machine compartment broken away showing the control of this invention.

Referring now more particularly to the drawing for a. descriptionof the invention, the reference numeral I represents a casing of non-magnetic metal and comprises two telescopically-arranged cups I l and I2 lwhich may be soldered together to effect a moisture-proof container.

The cup I2 has a reduced portion at its base to provide a shoulder I4 which engages one side of the edge I5 of a circular temperature-responsive element which edge I5 is secured on the other side by the lips l? of the cup il. ture-responsive element I6 preferably comprises several dished bimetallic discs t8 which are secured together at their center by an eyelet It passing through centrally located holes 2| in the discs lI8 so that the several discs I8 act in unison. The dished contour of the discs I8 aordsl a snap-acting movement to the central portions 22 thereof and the discs I8 are adapted to snap to the position shown in full lines in Fig. l when the temperature of said discs i8 drops below a predetermined temperature and to the position shown by the dotted lines when the temperature rises a certain amount above the aforementioned predetermined temperature. l

The temperature-responsive element it cornpr'ises iron or other magnetic material. lts travel is limited by a bolt 23 soldered to the base of cup l2 which bolt 2t is provided with a collar tl and with lock nuts 25 forming stops.

.ein electro-magnet 26 comprising two pole pieces 2l and a winding 28 is secured by straps 2@ of non-magnetic material to the cup Il to lie adjacent the temperature-responsive element it and include the central portion 22 thereof in its magnetic field, The winding is suppliedwith an alternating current through two leads 3l and 32 connecting respectively with two insulated binding posts 33 and 34 in the base of the cup ll.

When the temperature-responsive element it' is adjacent the electro-magnet 26 as shown by the full lines of Fig. 1, its central portion 22 lies directly in the magnetic eld of the magnet 26, and since the element I6 comprises magnetic material, many lines of magnetic force will pass through the central portion 22 of the element i6. When the temperature-responsive element i6 is remote from the electro-magnet 26, as/shown by the dotted lines, fewer of the magneticy lines of force will flow through the element I6 and the magnetic eld of the magnet 26 will be generally weakened. This affects the impedance of the electro-magnet 26 and results in a smaller current owing through the windings 28 of the same when the element I6 is in the position indicated lby the full lines than when in the position shown The tempcraa relay '35 which in turn controls a motor 55. To

this end one of the binding posts 3ft on the cupy ll is connected to a supply line 3l of alternating current by a lead 3B and the other binding post 33 is connected to a second supply line 39 through lead 4l, the winding 42 of the relay, a lead 43, the contact arm 44, the resistance wires l5 of a variable resistance d6, and lead lili.

The relay 35 has an armature lili, the magnetic pull of which is counterbalanced by a spring it so that when the current 4through the winding 42 of the relay 35 decreases, due to a movement of the temperature-responsive element lli to the right as shown in Fig. 1, the. spring Il@ pulls the armature 4B to the right and opens a contact 5l associated with the armature d8. When the element i6 moves to the left, the armature lo likewise is moved to the left by the increased magnetic pull of the relay winding 82, closes the contact l, and energizes the motor 35.

The invention also provides for adjustment of the temperature limits at which the element Contact arm M of I6 snaps toward and away from the pole pieces 21 of the electro-magnet 26. This isaccomplished by rotating the contact arm 44 of the variable resistance on the pivot 52, a movement to the right in Fig. l, for example, increases the voltage impressed on the winding 28 thereby increasing the current through the electro-magnet 26 so that it attracts the temperature-responsive element I6 more strongly and effects a movement thereof to the right at a higher temperature than formerly. The movement of the element I6 to the left likewise occurs. at a higher temperature than formerly.`

The increase or decrease in the current effected by the variable resistance also varies the pull exerted by the Winding 42 of the relay 35 on the armature 4B and a compensation for this variation in pullis required. One end of the spring 49, therefore, is secured to the contact arm 44 of the variable resistance 46 so that when the arm 44 is moved to increase the current, the tension on the spring 49 is also increased and vice versa. This varied tension is such that it counteracts the varied pull of the winding 42 of the relay 3.5 so that the contact 5l is open when the temperature-responsive element I6 is in the positionshown by the full lines of Fig. 1 and. is closed when the element I6 is in the position shown by the dotted lines of Fig. 1 regardless of the position of the contact arm 44.

The apparatus of this invention is adapted for controlling mechanical refrigerating apparatus. Referring particularly to Fig. 3 of the drawing, the reference numeral 55- represents a cabinet having an insulated food storage chamber 56 in the upper portion thereof. The lower portion of the cabinet 55 comprises a 'machine compart-l ment 51. An evaporator 58 is located in the upper portion of the storage chamber 56 and connects with a compressor 59 through the suction. conduit 6l. The compressor 6l is driven by a motor 62 and withdraws vapcrized refrigerant from the evaporator 58, compresses it and passes it through a tube 63 into an air cooled condenser 64 wherein the refrigerant vapor is liquefied. The liquefied refrigerant passes upwardly through a capillary tube '65 into the evaporator 58 where it evaporates and repeats the refrlgerating cycle just described.

The refrigerating apparatus is of the intermittently operated type and is regulated by the thermostatically-controlled switch of this inasueto vention. This is eected by securing the casing l@ enclosing the temperature-responsive element l5 and the electro-magnet Zt adjacent to the evaporator 53. IThe relay 35 and the variable resistance Lili are enclosed in a boi: 5t provided with an external knob (Si by means of which the the variable resistance @t may be moved baci: and forth along the resistance d5. The electrical connections are the same as already explained in connection with Fig. 1.

It will be apparent from the above that this invention provides a bimetallic control in which the electrical contacts are remote from the bimetallic element and do not require to be enclosed in a sealed casing to protect them from frost and moisture where these are present at the zone to be controlled. The absence of a sealed casing around the electrical contacts makes the use of flexible bellows or similar adjusting devices unnecessary.

While I have shown my invention in but one form, it will be apparent to those skilled in the art that it is not so limited, but is susceptible of various changes and modiiications without departing from the spirit thereof, and I desire, therefore, that only such limitations yshall-'be placed thereupon as are specifically' set forth in the appended claims.

What I claim is:

1. In a mechanical refrigerator, the combination of an insulated chamber, an evaporator for cooling the same, mechanism for supplying refrigerant to said evaporator, a control for said mechanism comprising an electro-magnet including a current-conducting winding, a temperature-responsive device, magnetic materialassociated therewith, said temperature-responsive device being adapted to move said magnetic material in the magnetic field of said magnet to change the impedance of said Winding in respense to changes in temperature of said temperature-responsive device, said temperature-responsive device being in heat exchange relationship with said evaporator and means responsive to changes in the impedance of said winding for controlling the supply of refrigerant to said evaporator.

l 2. In a mechanical refrigerator, the combination of an insulated chamber, an evaporator for cooling the same, mechanism for supplying refrigerant to said evaporator, a control for said mechanism comprising an electro-magnet including a current-conducting winding, a snapactingy temperature-responsive device, magnetic material associated therewith, said temperatureresponsive device being adapted to move said magnetic material in the magnetic field of said magnet to change the impedance of said winding in response to the snap-acting movement of l said temperature-responsive device, said temperheat from an enclosed chamber, the combination of mechanism for supplying refrigerant tov said evaporator, a control for said mechanism comprising an electro-magnet including a currentconducting Winding, a temperature-responsive device, magnetic material associated therewith,

said temperature-responsive device being adapted to move said magnetic material in the magnetic field of ,said magnet, to vary the impedance of said winding in response to changes in temperature of saidl evaporator, and means responsive to changes in the impedance of said winding for controlling the supply of refrigerant to said conducting winding, adjustable means for varying the current flowing through said Winding, a temperature-responsive device, magnetic material associated therewith, said temperaturerespensive device being adapted to move said magnetic material in the magnetic eld of said magnet to vary the impedance of said/Winding in response to changes in temperature of said evaporator, and means responsive to changes in the impedance of said winding for controlling the supply of refrigerant; to said evaporator.

5. A control Asystem for mechanical refrigerators of the type having an evaporator for absorbing heat from an enclosed chamber and a" mechanism for supplying refrigerant to said evaporator, said control systemv comprising a sealed casing disposed adjacent the evaporator, an electro-magnet provided with a current-conducting 'winding disposed in said casing, a temperature-responsive device having magnetic matei-iai associated therewith for movement by said temperature-responsive device within the field of said electro-magnet for varying the impedance thereof in response to the temperature of the evaporator, said temperature-responsive device and magnetic material also being disposed in said sealed casing, and means disposed outside the enclosed chamber and responsive to variations in the impedance of said electro-magnet for controlling the supply of refrigerant to said evaporator.

6. A control system for mechanical refrigerators of the type having an evaporator for absorbing heat from an enclosed chamber and a mechanism for supplying refrigerant to said evaporator, said control system comprising a sealed casing disposed adjacent the evaporator,

an electro-magnet provided with a current-conducting winding disposed in said casing, a temp'erature-responsive device having magnetic materialvassociated therewith for movement by Said temperature-responsive device within the iield ofrsaid electro-magnet for varying the impedance thereof in response to the temperature of the evaporator, said temperature-responsive device and magnetic material also being disposed in said sealed casing, means disposed outside the enclosed chamber and responsive to variations in 

